Personally I've always been more partial to these types of books or you might as well start with CompTIA's trifecta of security specialist or whatever they call it.
That being the A+, the Network+, and the security+. Be warned these tests do have it in them more so than you may think they're quite expensive too. Seeing as you're only 16 though you may be able to work a job that with a lot of downtime so you can study like the movie theater or similar.
So theoretically you could pull it off of turning 18 having all three of those certs and being basically leaps and bounds ahead of anyone of your fellow students.
That being said it would require a lot of hard work.
A great primer in 2018 is this book: https://www.amazon.com/Network-Programmability-Automation-Next-Generation-Engineer/dp/1491931256/
I did not write it nor do I have an investment in the authors. With that being said, I recommend this book to any networkers that consult me for network automation engineering information.
This book is slightly old, but still probably good/worthwhile:
https://www.amazon.com/Network-Programmability-Automation-Next-Generation-Engineer/dp/1491931256
This would be the second book I would probably look at (disclaimer: I haven't read this one whereas I read parts of the first book):
https://www.amazon.com/Mastering-Python-Networking-automation-programmability/dp/1839214678
Note, I know the authors of both of these books (so I could have biases in that way as well).
This is a good book for a beginner. Combined with Kirk Byer's introduction, which includes Netmiko, you'll be off to a good start.